It was known in the prior art of transit vehicle control systems to provide redundant control apparatus in relation to the one or more important component portions of the vehicle control system, such that a failure of some component portion would not prevent the operational movement of a vehicle along the roadway track. With such a redundant arrangement a spare component apparatus is provided to stand by each of those more important portions of the control system.
The present cost of transit systems requires the minimum number of roadway tracks to be installed because of the high expense of building those tracks underground or elevated, and therefore in effect a one lane vehicle roadway track is provided in each direction along which each transit vehicle passes. If any vehicle stops or fails to move it will block the whole roadway track. Since the real purpose of a transit vehicle system is to move passengers, the individual vehicles are desired to keep moving at all times.
A vehicle automatic train control or ATC apparatus is provided to control the operation of each train of vehicles, which train may consist of a plurality of coupled pairs of vehicle cars. Each pair of cars or each provided control car includes a complete ATC apparatus. The ATC apparatus interfaces with the wayside train control equipment to receive and/or transmit data used for the safe control of the train, such as speed command signals, station program stop information, identification, performance modification and door control signals. The vehicle ATC also receives inputs from car subsystems and from the operator's console in relation to desired operating modes and car status. The operational modes are ATO, MCS and Manual; in automatic train operation mode the propulsion request is provided by the propulsion and brake train lines with overspeed protection to keep actual speed from exceeding the commanded speed; in manual cab signal mode the operator responds to received speed commands on his console by controlling the propulsion and braking activity of the train; in manual mode the train control system on the vehicle is bypassed, but the operator is limited to a predetermined speed such as 20 KPH and responds to orders from the central control operator.
One of the failures that can stop a transit vehicle system is the breakdown or failure of the automatic train control system on any one train of vehicles. The several backup modes of operation, atomatic, manual with cab signalling and manual have their common points, for example, automatic and MCS require that the automatic train protection portion of the automatic train control or ATC equipment satisfactorily operates, and if that particular part of the equipment fails, then a manual mode of operation is required. The manual mode is generally limited to something in the order of 20 KPH because of the system safety reqirements, and in addition it is desired to move passengers at fast speeds and at close headways which an operator has difficulty doing.
In an article entitled The Bartd Train Control System that was published in Railway Signalling and Communications for December 1967 at pages 18-23 the train control system for the San Francisco Bay Area Rapid Transit District was described. Other articles relating to the same train control system were published in the IEEE Transactions on Communication Technology for June 1968 at pages 369-374, in Railway Signalling and Communications for July 1969 at pages 27-38, in the Westinghouse Engineer for March 1970 at pages 51-54, in the Westinghouse Engineer for July 1972 at pages 98-103, and in the Westinghouse Engineer for September 1972 at pages 145-151. A general description of the train control system now being provided for the Sao Paulo, Brazil Metro is set forth in an article published in the Conference Record of the October 1977 Meeting of the IEEE Industry Application Society at pages 1105-1109. A description of the train control system now being provided for the Atlanta Airport People Mover is set forth in an article published for the 28th Conference of the IEEE Vehicular Technology Group at Denver, Colo. in March 1978, and in an article entitled The Sao Paulo Metro Automated Transit System that was published for the Rapid Transit Conference of the American Public Transit Association in Chicago, Ill. in June 1978.
A general description of microprocessors suitable for use in the present invention and related peripheral devices is provided in the Intel 8080 Microcomputer Systems Users Manual currently available from Intel Corporation, Santa Clara, Calif. 95051.